Carrier 38QN - Compressor Overview; Mechanical Compressor Failures

24-VOLT WIRING
LINE VOLTAGE
PASS SUPPLY WIRE THRU
METALLIC LOOP TWICE ON
UNITS WITH NAMEPLATE
RLA OF 14 AMPS OR LESS
SUPPLY WIRE
THERMOSTAT
SUBBASE
INDOOR UNIT
TERMINAL
BOARD
FIELD LINE VOLTAGE SUPPLY WIRE
OUTDOOR UNIT
TERMINAL
BOARD
C — Contactor _Common Potential
LLPS — Liquid Line Low-Pressure Switch - Factory Wiring (field connected)
TB — Terminal Board
_Field-Supplied Wiring
Fig. 15 — Wiring Connections for Service Sentry and Solid-State Time Guard II
Compressor — The compressor is the heart of the
refrigeration system. It pumps refrigerant through the
system. If it malfunctions, the whole system suffers.
The compressor is an electrical (as well as mechanical)
device. Extreme caution should be exercised when work¬
ing near compressors. Power should be shut off, if
possible, for most troubleshooting techniques. Refrig¬
erants in system present other safety hazards. Always
wear safety glasses and gloves when handling refrigerants.
Compressor failures are classified in 2 broad failure
categories, mechanical and electrical. Both types are
discussed below and on page 13.
MECHANICAL FAILURES — Compressor is a
mechanical pump driven by an electric motor contained
in a welded or hermetic shell. In a mechanical failure,
motor or electrical circuit appears normal, but com¬
pressor does not function normally.
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